Plastic trash bags are produced and sold on an extensive scale in a variety of shapes and sizes. The vast majority of these bags are made of polyethylene film. The bags are generally quite simple, having an open end with straight sidewalls, often joined by a seam(s), with a closed bottom. The trash bags also serve as trash can liners. Conventionally, the upper edge of the bag is rolled over the upper lip of the trash container. A problem, however, is how to keep the bag open and attached to the top of the container. Some trash cans are described as having means to secure the trash bag to the container, such as U.S. Pat. No. 4,738,478 (Bean), who describes a retaining ring with an elastic band that fits within a U-shaped track in the rigid ring. The bag is retained on the trash can by the elastic band. Of course, this is only a limited solution. It has also been proposed to place an elastic band on the trash bag itself in U.S. Pat. No. 4,509,570. The elastic band is located in a hem at the top of the trash bag along its full circumference in a stretched condition. However, this construction has disadvantages in terms of cost, manufacturing and packaging. A major problem with the construction is that the bag top will gather (see FIG. 3), whereas most bags are required to fold into a flat sheet for efficient manufacturing and packaging, which is virtually impossible with a gathered bag. U.S. Pat. No. 4,747,701 (Perkins) proposes a solution to the gathering problem. Perkins places a wide elastic band at the rim of the bag which has the same circumference as the main plastic side portions of the bag. The wide elastic band (2 to 5 inches wide) is then turned over onto the rim of the trash container. This allegedly causes a slight elongation of the elastic band which will allegedly retain the bag on the rim. This is an expensive solution, as significant amounts of elastic are used. Additionally, unless the trash container rim circumference is closely matched to that of the trash bag, this method is likely ineffective. Too large a trash container will create excessive shear stresses in the elastic increasing the likelihood of detachment from the main bag. A trash container rim with a circumference about the same as or smaller than the trash bag circumference is unlikely to create enough elastic retraction force to retain the bag.
Another area of concern is how to close the bag following use. Conventional closures include twist ties (metal wires) or plastic closures such as discussed in U.S. Pat. No. 4,477,950 (Cisek, et al.). It has also been proposed to attach closure elements to the bags themselves, e.g., U.S. Pat. No. 3,974,960 (Mitchell) (a plastic tie strip), and U.S. Pat. Nos. 4,913,560, 4,906,108 and 4,813,794 (all to Herrington or Herrington, et al.), that describe tacky plastic closures. The use of draw strings or tape is also popular as discussed in U.S. Pat. Nos. 4,762,430 (Ballard), 4,813,792 (Belmont, et al.) and 4,813,793 (Belmont, et al.). However, these closures do not address the problems of how to keep the bag open and attached to the trash container.
The present invention is directed at solving some of the problems with the prior art by providing a simple means that will serve to keep a bag open in use while also serving as a closure, which is advantageous in terms of cost, packaging and manufacture.